Buitreraptor
Buitreraptor was a rooster-size predatory dinosaur belonging to the dromaeosaurid family. It was found in Argentina, and was described in 2005. The fossilized bones were found in 2005 in sandstone in Patagonia, Argentina - by an excavation led by Peter Makovicky, curator of dinosaurs at the Field Museum in Chicago). Buitreraptor was discovered in the same fossil site that had earlier yielded Giganotosaurus, one of the largest known carnivorous dinosaurs.Makovicky, Peter J., Apesteguía, Sebastián & Agnolín, Federico L. (2005). The earliest dromaeosaurid theropod from South America. Nature, 437: 1007–1011. Buitreraptor gonzalezorum is the only known species of the genus Buitreraptor. The genus name means "vulture raider", from the Spanish word buitre meaning vulture. Furthermore, the area in which the remains were found is called La Buitrera. '' (back) skeletons at the Field Museum of Natural History.]] Description Buiteraptor was a rather small species. In 2010 Gregory S. Paul estimated the length at 1.5 metres, the weight at three kilograms.1 Buitreraptor has some different physical features than typical northern dromaeosaurs, such as Velociraptor. Buitreraptor has a slender, flat, extremely elongated snout with many small teeth that lack meat-tearing serrations or cutting edges and are grooved, strongly recurved and flattened.23 From this, the scientists who initially described it concluded that this dinosaur was not a hunter of relatively large animals like some other dromaeosaurs, but rather a hunter of small animals such as lizards and mammals. The forelimbs of Buitreraptor were long and ending in hands with three fingers. The fingers were proportionarly shorter than in other dromaeosaurids, and of essentially the same length, contrary to most of its relatives, which had fingers of different length, with the second finger being considerably longer. The body as a whole was also very elongated, with a shallow ribcage. The sickle claw at the second toe of the foot was relatively short and broad. Feathers No fossil discoveries have been made of any feathers of Buitreraptor. However, there are relatives like Microraptor and Sinornithosaurus, of which fossils with preserved feathers are known. Since its close relatives had feathers, it is likely that Buitreraptor also was feathered. According to Apesteguia, this is comparable to reconstructing an extinct monkey with fur because all modern monkeys have fur. Paleobiogeography Buitreraptor lived about 90 million years ago, when South America was an isolated continent like Australia today. Buitreraptor has some different physical features than typical northern dromaeosaurs, such as Velociraptor. Buitreraptor has a slender snout with teeth that lack meat-tearing serrations. From this, the scientists who initially described it concluded that this dinosaur was not a hunter of relatively large animals like some other dromaeosaurs, but rather a hunter of small animals such as lizards and mammals. It most likely had feathers. Other than Buitreraptor, the only other known dromaeosaurs from the southern continents are Neuquenraptor, Austroraptor, and Unenlagia from South America (discovered earlier in 2005), Rahonavis (once thought to be a true avian bird) from Madagascar, and unidentified dromaeosaur-like teeth from Australia. This discovery in the Southern Hemisphere helps to clarify that the dromaeosaur family was more widely dispersed around the world than previously thought. Evidence indicates that dromaeosaurs first appeared in the Jurassic Period, when all the continents were much closer together than they are today. It is possible that dromaeosaurids originated on the ancient continent Laurasia in the north and migrated to southern Gondwana, since the species known from the southern hemisphere bear distinctive characteristics not shared by their northern relatives. Phylogeny and discussion about flight References External links * BBC News: Bird-like dinosaur forces rethink, 13-Oct-2005 * Drawing and some details from the Natural History Museum, London. * National Science Foundation web site Category:Cretaceous dinosaurs Category:Dinosaurs of South America Category:Dromaeosaurs